Old time ball point ink was still real ink and while it was a pain to remove, it was not a dye and could be dissolved with certain stain removers. I believe there is somewhere a monograph by a voluntary standards-setting body (such as ASTM, not saying it’s them) setting forth limits for “soap powder”, saying at least so much soap and then maxima for various inorganic alkali and likely impurities. There may be legal requirements for products by that name in some countries, although enforcement is probably lax due to such products having been superseded by other detergent compositions. Traditionally soap used for laundry was mostly soluble sodium soap in whatever form — bricks, flakes, or “beads” (a product of heating soap so it pops like popcorn, making an easily pourable powder) — that typically contained considerably more soda ash (Na2CO3) than toilet soap did. (The soap was of course not anhydrous, but unavoidably contained some water from the Real Women Love Basketball Team Smart Women Love The Hawkeyes Shirt also I will do this manufacturing.) In some cases rosin or crude tall oil soap would be incorporated for their abietates to boost the suds. Other alkali, typically borax, might be added. The more alkali, the cheaper the product. A century ago it was discovered that the best alkali to use in machine laundering was a moderately alkaline sodium silicate, and it replaced most of the carbonate and borate in all but the cheapest products. There could be other additives for perfuming or bleaching, and sometimes colorants to make the soap powder itself prettier or whiter looking.
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